package com.ld.xuanKe.listener;

import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.read.listener.ReadListener;
import com.alibaba.excel.util.ListUtils;
import com.ld.xuanKe.entity.User;
import com.ld.xuanKe.service.UserService;
import com.ld.xuanKe.service.impl.UserServiceImpl;
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.WebApplicationContext;

import java.util.List;

import static org.apache.struts2.ServletActionContext.getServletContext;

/**
 * @ProjectName xuanKe
 * @ClassName MyUploadUserDataListener
 * @Author 刘邓
 * @Date 2023-12-10 19:39
 */
public class MyUploadUserDataListener implements ReadListener<User> {
	/**
	 * 每隔5条存储数据库，实际使用中可以100条，然后清理list ，方便内存回收
	 */
	private static final int BATCH_COUNT = 100;
	/**
	 * 缓存的数据
	 */
	private List<User> cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
	/**
	 * 假设这个是一个DAO，当然有业务逻辑这个也可以是一个service。当然如果不用存储这个对象没用。
	 */
	private int all = 0;
	private int success = 0;
	private UserService userService;


	public MyUploadUserDataListener() {
		ApplicationContext applicationContext = (ApplicationContext) getServletContext().getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
		userService = (UserServiceImpl) applicationContext.getBean(UserService.class);
	}


	/**
	 * 这个每一条数据解析都会来调用
	 *
	 * @param data    one row value. Is is same as {@link AnalysisContext#readRowHolder()}
	 * @param context
	 */
	public void invoke(User data, AnalysisContext context) {
		cachedDataList.add(data);
		// 达到BATCH_COUNT了，需要去存储一次数据库，防止数据几万条数据在内存，容易OOM
		if (cachedDataList.size() >= BATCH_COUNT) {
			saveData();
			// 存储完成清理 list
			cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
		}
	}


	/**
	 * 所有数据解析完成了 都会来调用
	 *
	 * @param context
	 */
	public void doAfterAllAnalysed(AnalysisContext context) {
		// 这里也要保存数据，确保最后遗留的数据也存储到数据库
		saveData();
	}

	/**
	 * 加上存储数据库
	 */
	private int saveData() {
		all += cachedDataList.size();
		for (User user : cachedDataList) {
			user.setStatus(0);
			int i = userService.add(user);
			success += i;
		}
		getServletContext().setAttribute("all", all);
		getServletContext().setAttribute("success", success);
		return success;
	}
}
